This conference on the Endocrinology of Embryo-Endometrial Interactions is the only one of the 16 official satellite symposia and 44 minisymposia of the Ninth International Congress on Endocrinology (N.I.C.E. 92) devoted to this important subject. This symposium is organized to provide a common ground for interaction between authoritative active investigators in the various disciplines which define state-of-the-art research in the endocrinology of embryo-endometrial interactions. The meeting will establish a forum for free communication through which participants may evaluate current research, critically assess prevalent theories and methods and promote development of new strategies and concepts if needed. The working conference will focus on the biochemical and molecular mechanisms that program the generation of maternal and embryonic signals that coordinate development of uterine receptivity to the embryo. Critical discussions will define whether these signals (hormones, growth factors, cytokines) act directly on the uterine epithelial cell and/or indirectly via uterine stromal cells to transform the uterus sequentially from non-receptive to ovo-receptive to refractory. Interdisciplinary discussions of endometrial cell type responses to blastocyst signals will identify the cell-cell, cell-substratum processes by which embryonic signals are modified in different species to establish and maintain gestation. Examination of in vitro models to study embryo (human, rodent, recombinant bovine) - endometrial relationships will serve to integrate the ideas exchanged. This proposal seeks funds to underwrite the participation by recognized American investigators in this pivotal international symposium. In addition to its fundamental importance to the study of the regulatory biology of intercellular endocrinology the relevance of embryo-endometrial interactions in medical and veterinary clinics and in biotechnology facilities increases each year. It is important to sustain and extend our leadership in this area. This is the only avenue available to assist the participation of a strong cadre of American scientists in this symposium. No funds are available via NICE 92.